1. Field of the Invention
The present invention relates to a method for manufacturing an elastic wave device and the elastic wave device.
2. Description of the Related Art
When a surface acoustic wave device is manufactured, a mother substrate is segmented into individual piezoelectric substrates as units of electronic components. In International Publication No. WO 08/018452, first, a metal film is formed on the overall upper surface of a mother substrate. Then, the mother substrate on which the metal film has been formed is segmented into individual piezoelectric substrates.
In Japanese Unexamined Patent Application Publication No. 2006-80921 and International Publication No. WO 13/035819, a metal film or a conductor film is formed not only on the upper surface of a piezoelectric substrate but also on the side surfaces thereof. With this, in Japanese Unexamined Patent Application Publication No. 2006-80921, charging of a resin member in a surface acoustic wave chip is prevented. In International Publication No. WO 13/035819, an electromagnetic wave shield effect of an electronic component is enhanced.
In the manufacturing method disclosed in International Publication No. WO 08/018452, segmentation is performed after the metal film is formed. In this case, the metal film is possibly extended in the segmentation because of high ductility and malleability of metal. For this reason, there is a risk that the metal film protrudes to the lateral sides from end edges of the segmented piezoelectric substrates or reaches parts of the side surfaces thereof.
On the other hand, in the manufacturing methods disclosed in Japanese Unexamined Patent Application Publication No. 2006-80921 and International Publication No. WO 13/035819, the conductor film or the metal film is formed not only on the overall upper surface of the piezoelectric substrate but also on the side surfaces thereof.
Accordingly, in each of elastic wave devices provided by the manufacturing methods disclosed in International Publication No. WO 08/018452, Japanese Unexamined Patent Application Publication No. 2006-80921 and International Publication No. WO 13/035819, there is a risk that the metal film may make contact with other conductive parts and other electronic components and short-circuit breakdown occurs. In recent years, a metal film as a heat dissipating film has been tried to be provided on one main surface of a piezoelectric substrate in order to enhance heat dissipation property. Also in the configuration provided with the heat dissipating film, contact between the heat dissipating film and other portions and contact between the heat dissipating film and other conductive parts such as electronic components are required to be prevented.